Place the pineapple on a cutting board, on its side. Cut off the top and bottom caps about 1/2 inch thick.
Stand up the pineapple on the cutting board, and trim off the thick skin with a sharp knife.
Cut the pineapple flesh in half through the center and then cut each half in two. Slice off the inner hard rind off the flesh and finally, cut each quarter into about 1-inch chunks.
Store cut pineapple in a container with a lid, in the refrigerator, until ready to use.
Combine pineapple juice, soy sauce, white wine vinegar, pressed garlic, sliced onion, and brown sugar in a bowl and whisk well.
Cut boneless, skinless chicken thighs in half and add it to a large zip-lock bag.
Pour the marinade into the bag, close it well, and lay the bag on a large plate. Place chicken into the refrigerator to marinate overnight (or for at least 2 hours).
Grilling chicken kebabs:
Prepare the coals and preheat the grill.
Take chicken out of the marinade but save the marinade to cook and use as sauce/glaze. Skewer chicken pieces and pineapple chunks, alternating 1 piece of pineapple to 2 pieces of chicken. It’s best to fold or roll each piece of chicken thigh meat.
Spray each skewer with some cooking oil spray all around and place skewers onto the grill grate. Cook the skewers turning them a quarter of the way every 4-5 minutes. Use meat thermometer to take the temperature on the thickest part. Chicken is safely cooked when reaches 165° internally.
Simmer leftover chicken marinade either right on the grill, in the metal sauce pot, or on stove-top until about half the amount while chicken is cooking.
Brush cooked with chicken kebabs with some of the sauce.